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A-Line Staffing Solutions Interview Questions

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Machine Learning

Job Recommendation

RMS Error

Lasso vs Ridge

Bagging vs Boosting

FAQ Matching

Data Structures & Algorithms

Given an integer N, write a function that returns all of the prime numbers up to N

Prime to N

Moving Window

Given a json string with nested objects, write a function that flattens all the objects to a single key-value dictionary.

Flatten JSON

This problem involves identifying duplicate numbers in a list of integers. The function should return a list of the duplicate numbers.

Find Duplicate Numbers in a List

Given a list of strings, write a function that returns the longest common prefix

Common Prefix

Last Transaction

Write a query to get the number of friends of a user that like a specific page

Liked Pages

Flight Records

Cumulative Distribution

Given a users table, write a query to get the cumulative number of new users added by the day, with the total reset every month. 

Cumulative Reset

Statistics

P-value to a Layman

Reducing Error Margin

What are the assumptions of linear regression?

Assumptions of Linear Regression

Using R Squared

Unbiased Estimator

Analytics

How would you measure the success of an online marketplace introducing an audio chat feature given a dataset of their usage?

Audio Chat Success

How would you find out if an increase in user conversion rates after a new email journey is casual or just part of a wider trend?

Causal Email Journey 

How would you analyze the dataset to understand exactly where the revenue loss is occurring?

Evaluating Revenue Decline

Describing a data project and its challenges

Hurdles In Data Projects

Strategically resolving misaligned expectations with stakeholders for a successful project outcome

Stakeholder Communication

When an interviewer asks a question along the lines of:

<ul>
<li>What would your current manager say about you? What constructive criticisms might he give?</li>
<li>What are your three biggest strengths and weaknesses you have identified in yourself?</li>
</ul>

How would you respond?

When asked about your strengths in an interview, what is an effective way to respond?

When asked about your strengths in an interview, what is an effective way to respond?

Your Strengths and Weaknesses I

Which of the following is an acceptable strategy when discussing weaknesses in an interview?

Which of the following is an acceptable strategy when discussing weaknesses in an interview?

Your Strengths and Weaknesses II

What do you tell an interviewer when they ask you what your strengths and weaknesses are?

Your Strengths and Weaknesses

Brainteasers

When an interviewer asks you a question along the lines of:

<ul>
<li>Why did you apply to our company?</li>
<li>What are you looking for in your next job?</li>
<li>What makes you a good fit for our company?</li>
</ul>

How should you respond?

When asked 'What are you looking for in your next job?' in an interview, how can you tie the company's employee benefits into your response?

When asked 'What are you looking for in your next job?' in an interview, how can you tie the company's employee benefits into your response?

Why Do You Want to Work With Us I

How can company values be used effectively in an interview when asked 'What makes you a good fit for our company?'

How can company values be used effectively in an interview when asked 'What makes you a good fit for our company?'

Why Do You Want to Work With Us II

When responding to the question 'Why did you apply to our company?' during an interview, what aspect should you highlight?

When responding to the question 'Why did you apply to our company?' during an interview, what aspect should you highlight?

Why Do You Want to Work With Us III

How would you answer when an Interviewer asks why you applied to their company?

Why Do You Want to Work With Us

Describe a data project you worked on. What were some of the challenges you faced?

How would you explain what a p-value is to someone who is not technical?

What does a p-value in a statistical test represent?

What does a p-value in a statistical test represent?

P-value to a Layman I

In a statistical test, how does a low p-value (less than 0.05) influence our decision about the null hypothesis?

In a statistical test, how does a low p-value (less than 0.05) influence our decision about the null hypothesis?

P-value to a Layman II

What are the assumptions of linear regression?

Which assumption of the residuals of the standard linear regression model can not be overcome by increasing the sample size?

Regression assumptions

Let’s say that you’re training a classification model.

How would you combat overfitting when building tree-based models?

Let's say that you're training a classification model.   How would you combat overfitting when building tree-based models?

Overfit Avoidance

How would you handle the data preparation for building a machine learning model using imbalanced data?

Addressing imbalanced data in machine learning through carefully prepared techniques.

Data Preparation for Imbalanced Data

Let’s say we’re comparing two machine learning algorithms. In which case would you use a bagging algorithm versus a boosting algorithm? 

Give an example of the tradeoffs between the two.

In machine learning, when would you use a bagging algorithm over a boosting algorithm?

In machine learning, when would you use a bagging algorithm over a boosting algorithm?

Bagging vs. Boosting

Talk about a time when you had trouble communicating with stakeholders. How were you able to overcome it?

Given a string, write a function to determine if it is palindrome or not.

Note: A palindrome is a word/string that is read the same way forward as it is backward, e.g. <code>&#39;reviver&#39;</code>, <code>&#39;madam&#39;</code>, <code>&#39;deified&#39;</code> and <code>&#39;civic&#39;</code> are all palindromes, while <code>&#39;tree&#39;</code>, <code>&#39;music&#39;</code> and <code>&#39;person&#39;</code> are not palindromes.

Example:

Input:

<pre tabindex="0" class="chroma"><code>word1 = &#34;tree&#34;
word2 = &#34;radar&#34;
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>def is_palindrome(word1) -&gt; False
def is_palindrome(word2) -&gt; True
</code></pre>

Given a string, write a function to determine if it is palindrome or not.

String Palindromes

Explain the difference between the XGBoost and random forest algorithms and give an example where you would use one over the other.

Why might a data scientist choose to use XGBoost instead of Random Forest for a particular machine learning task?

Why might a data scientist choose to use XGBoost instead of Random Forest for a particular machine learning task?

XGBoost vs Random Forest: Choice

Xgboost vs Random Forest

How does random forest generate the forest? Additionally, why would we use it over other algorithms such as logistic regression?

What happens when you average the output on multiple decision trees?

What happens when you average the output on multiple decision trees?

Average Trees

Random Forest Explanation

Let’s say that you work at a B2B SAAS company that’s interested in testing the pricing of different levels of subscriptions.

Your project manager comes to you and asks you to run a two-week-long A/B test to test an increase in pricing.

How would you approach designing this test? How would you determine whether the increase in pricing is a good business decision?

Testing Price Increase

A/B Testing

Tell me about a project in which you had to clean and organize a large dataset.

Describing a real-world data cleaning and organization project

Data Cleaning Experiences

Data Pipelines

Let’s say we want to launch a re-design of a landing page to improve the click-through rate. We can do this by implementing an AB test.
Given that we launch an AB test, how would you infer if the results of the click-through rate were statistically significant or not?

How can you accurately conclude if the results of an A/B test, conducted to evaluate the effectiveness of a landing page redesign, are statistically significant?

How can you accurately conclude if the results of an A/B test, conducted to evaluate the effectiveness of a landing page redesign, are statistically significant?

Statistically Significant Test

Precisely ascertain whether the outcomes of an A/B test, executed to assess the impact of a landing page redesign, exhibit statistical significance.

What are the key differences between classification models and regression models?

What is the MOST important difference between regression and classification models?

What is the MOST important difference between regression and classification models?

Classification vs Regression

Classification and Regression

Let’s say that your company is running a standard control and variant AB test on a feature to increase conversion rates on the landing page. The PM checks the results and finds a .04 p-value.

How would you assess the validity of the result?

Experiment Validity

Given an integer <code>N</code>, write a function that returns a list of all of the prime numbers up to <code>N</code>.

Note: Return an empty list there are no prime numbers less than or equal to <code>N</code>.

Example:

Input:

<pre tabindex="0" class="chroma"><code>N = 3
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>def prime_numbers(N) -&gt; [2,3]
</code></pre>

Regularization and cross-validation are two common techniques used to improve the performance of machine learning algorithms.

When should you use one versus the other?

Given the choices below, which one is an example of a scenario where we should be using regularization?

Given the choices below, which one is an example of a scenario where we should be using regularization?

Regularization Example

Regularization and Validation

What’s the difference between Lasso and Ridge Regression?

Under what circumstances is it recommended to use Lasso regression over Ridge regression?

Under what circumstances is it recommended to use Lasso regression over Ridge regression?

How would you convey insights and the methods you use to a non-technical audience?

Making data-driven insights actionable for those without technical expertise

Simple Explanations

What’s the relationship between PCA and K-means clustering?

What does the variable “k” in k-means clustering refer to?

What does the variable "k" in k-means clustering refer to?

Input of K-means

PCA and K-Means

The Fibonacci sequence is a series of numbers in which each number is the sum of the two preceding ones, usually starting with 0 and 1. It is often used in algorithm examples, and is defined by the following formula: F(n) = F(n-1) + F(n-2), with F(0) = 0 and F(1) = 1.

Your task is to implement the Fibonacci algorithm in three different methods:
1. Recursively
2. Iteratively
3. Using Memoization

Example 1:

Input:

<pre tabindex="0" class="chroma"><code>n = 5
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>fibonacci(n) -&gt; 5
</code></pre>

Example 2:

Input:

<pre tabindex="0" class="chroma"><code>n = 10
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>fibonacci(n) -&gt; 55
</code></pre>

The Fibonacci sequence starts as follows: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55…

This question requires the implementation of the Fibonacci sequence using three different methods: recursively, iteratively, and using memoization.

Implementing the Fibonacci Sequence in Three Different Methods

Let’s say you’re a data engineer at Fidelity Investments, and you’re running a SQL query on a cloud-based data warehouse. All cluster resources and network health metrics look normal, but the query is still taking over 10 minutes to complete.

How would you go about diagnosing and improving the performance of this query?

How would you diagnose and speed up a slow SQL query when system metrics look healthy?

Slow SQL Query

Query Optimization

Let’s say you work as a data scientist at a bank.

You are tasked with building a decision tree model to predict if a borrower will pay back a personal loan they are taking out.

<ol>
<li>How would you evaluate whether using a decision tree algorithm is the correct model for the problem?</li>

<li>Let’s say you move forward with the decision tree model. How would you evaluate the performance of the model before deployment and after?</li>
</ol>

Decision Tree Evaluation

How would you tackle multicollinearity in multiple linear regression?

Multicollinearity in Regression

You’re given a string that may contain the characters <code>{</code>, <code>}</code>, <code>[</code>, <code>]</code>, <code>(</code>, and <code>)</code>.

Task: Verify that the string is balanced. A balanced string is one where every opening character, <code>{</code>, <code>[</code>, or <code>(</code>, has a corresponding closing character, <code>}</code>, <code>]</code>, or <code>)</code>.

Write a function called <code>is_balanced(string: str) -&gt; bool</code> which verifies the balance of a string.

Example:

<pre tabindex="0" class="chroma"><code>is_balanced(&#39;(())[]{}&#39;) -&gt; True
</code></pre>

<pre tabindex="0" class="chroma"><code>is_balanced(&#39;{([(){}])()}&#39;) -&gt; True
</code></pre>

<pre tabindex="0" class="chroma"><code>is_balanced(&#39;{}[]())&#39;) -&gt; False
</code></pre>

<hr/>

Write a function that tests whether a string of brackets is balanced.

The Brackets Problem

In the context of hypothesis testing, what are type I errors (type one errors) and type II errors (type two errors)? What is the difference between the two?

Bonus: Describe the probability of making each type of error mathematically.

What is the difference between type I and type II errors?

Type I and II Errors

Let’s say you want to test the close friends feature on Instagram Stories.

How would you make a control group and test group to account for network effects?

What could be a potential risk when Facebook segments the metrics of the user interface change by market or demographic groups?

What could be a potential risk when Facebook segments the metrics of the user interface change by market or demographic groups?

Network Experiment Design I

What is the primary metric that Facebook should monitor if it decides to make the user interface of its posting feature more like Instagram's?

What is the primary metric that Facebook should monitor if it decides to make the user interface of its posting feature more like Instagram's?

Network Experiment Design II

If Facebook changes its user interface to mimic Instagram's, which adverse effect should they anticipate and monitor?

If Facebook changes its user interface to mimic Instagram's, which adverse effect should they anticipate and monitor?

Network Experiment Design III

Network Experiment Design

Given two strings, write a function to return <code>True</code> if the strings are anagrams of each other and <code>False</code> if they are not.

Note: A word is not an anagram of itself.

Example 1:

Input:

<pre tabindex="0" class="chroma"><code>string_1 = &#34;listen&#34;
string_2 = &#34;silent&#34;
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>True
</code></pre>

Example 2:

Input:

<pre tabindex="0" class="chroma"><code>string_1 = &#34;banana&#34;
string_2 = &#34;bandana&#34;
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>False
</code></pre>

Valid Anagram

Challenge

<h3>Job Description</h3><div>Job Description<div>Title: Programmer Analyst VI – Data Warehouse Business Analyst Location: Lansing, MI (Hybrid) Note: This is a W2 contract role – 1099, C2C, and 3 rd party candidates will NOT be considered This position plays a critical role in supporting programs by ensuring accurate and timely data is available for eligibility determinations, reporting, and program management. This position supports the Eligibility Data Warehouse Team, which provides critical data to support eligibility determinations. The Business Analyst will serve as a liaison between business stakeholders and technical teams, ensuring accurate data analysis and reporting using SQL-based tools. This role focuses on understanding business needs, translating them into actionable reporting requirements, and creating ad hoc queries and dashboards to support decision-making and compliance with federal and state requirements. Position Duties: · Collaborate with program staff and technical teams to gather and document business requirements· Assist stakeholders in defining reporting/ETL requirements and provide guidance on data interpretation· Perform data quality checks and troubleshoot reporting issues to ensure accuracy and compliance· Support ongoing enhancements and integrations related to data reporting and analytics· Participate in process improvement initiatives, gap analysis, and change management activities· Provide training and technical support to end users for reporting tools and processes· Assist in differentiating between defects and new requirements· Develop training content· Design, develop, and implement test plans for applications or subsystems· Create or collect test data and execute approved tests to determine the accuracy of program logic to produce desired results· Participate in artifact reviews with peers, system specialists, Enterprise Security and other department entities to ensure IT solutions adhere to department and agency policies, standards, or guidelines· Identify security requirements and standards· Develop and execute ad hoc SQL queries to extract, analyze, and validate data· Create and maintain reports and dashboards using SQL-based tools to meet reporting needs Position Qualifications: · 5+ years of experience as a Business Analyst (BA)· 5+ years of experience with SQL· 5+ years of experience working in Agile methodologies· A minimum of a Bachelor’s Degree in Information Technology or other related field</div></div>

Title: Programmer Analyst VI – Data Warehouse Business Analyst

Location: Lansing, MI (Hybrid)

Note: This is a W2 contract role – 1099, C2C, and 3 rd party candidates will NOT be considered

This position plays a critical role in supporting programs by ensuring accurate and timely data is available for eligibility determinations, reporting, and program management. This position supports the Eligibility Data Warehouse Team, which provides critical data to support eligibility determinations. The Business Analyst will serve as a liaison between business stakeholders and technical teams, ensuring accurate data analysis and reporting using SQL-based tools. This role focuses on understanding business needs, translating them into actionable reporting requirements, and creating ad hoc queries and dashboards to support decision-making and compliance with federal and state requirements.

Position Duties:

· Collaborate with program staff and technical teams to gather and document business requirements
· Assist stakeholders in defining reporting/ETL requirements and provide guidance on data interpretation
· Perform data quality checks and troubleshoot reporting issues to ensure accuracy and compliance
· Support ongoing enhancements and integrations related to data reporting and analytics
· Participate in process improvement initiatives, gap analysis, and change management activities
· Provide training and technical support to end users for reporting tools and processes
· Assist in differentiating between defects and new requirements
· Develop training content
· Design, develop, and implement test plans for applications or subsystems
· Create or collect test data and execute approved tests to determine the accuracy of program logic to produce desired results
· Participate in artifact reviews with peers, system specialists, Enterprise Security and other department entities to ensure IT solutions adhere to department and agency policies, standards, or guidelines
· Identify security requirements and standards
· Develop and execute ad hoc SQL queries to extract, analyze, and validate data
· Create and maintain reports and dashboards using SQL-based tools to meet reporting needs

Position Qualifications:

· 5+ years of experience as a Business Analyst (BA)
· 5+ years of experience with SQL
· 5+ years of experience working in Agile methodologies
· A minimum of a Bachelor’s Degree in Information Technology or other related field

<h3>Job Description</h3><div>Job Description<div>R&D Senior Engineer – Specimen Management / Medical Devices Location: Franklin Lakes, NJ Rate: $55–$60/hr on W-2 (No C2C)⏱ Duration: Long-term contractPosition OverviewWe are seeking an experienced R&D Senior Engineer to serve as a key contributor within a Research & Development team supporting a Specimen Management / Specimen Acquisition Platform. This role requires advanced engineering expertise, strong technical judgment, and the ability to independently solve complex product development challenges in a regulated medical device environment.The ideal candidate works under general direction, determines technical approaches independently, contributes to projects of significant impact, and may lead smaller-scope initiatives. This position plays a critical role in design, testing, verification, validation, and risk-based product development.Key ResponsibilitiesProduct Development & Technical Leadership<ul><li>Contribute to R&D projects of considerable scope or lead smaller engineering initiatives.</li><li>Independently determine and develop technical approaches to solve complex engineering problems.</li><li>Apply sound engineering principles to deliver imaginative, practical, and data-driven solutions.</li><li>Support material, design, and process changes through formal design control processes, ensuring timely and successful completion of assigned work.</li></ul>Design, Testing & Validation<ul><li>Design and develop in vivo and in vitro models to evaluate product features and improvements.</li><li>Plan, execute, and analyze Design of Experiments (DOE).</li><li>Develop robust test methods, design test fixtures, and perform Measurement System Analysis (MSA).</li><li>Execute and document bench studies, tolerance stack-up analyses, design verification, and validation activities.</li><li>Support vendor interactions, materials selection, and component specifications.</li></ul>Data Analysis & Reporting<ul><li>Perform statistical analysis, regression analysis, and develop transfer functions.</li><li>Collect, record, interpret, and analyze experimental data.</li><li>Prepare technical reports and present findings to peers and business leadership.</li><li>Provide advanced engineering input to support business cases for new product opportunities.</li></ul>Quality & Compliance<ul><li>Ensure compliance with quality system requirements, policies, and procedures.</li><li>Apply risk-based development approaches aligned with medical device regulations.</li><li>Promote quality awareness and sound engineering practices across the team.</li></ul>Cross-Functional Collaboration<ul><li>Participate in and lead technical, DFSS, design, and cross-functional reviews.</li><li>Direct associates and lead small cross-functional groups when required.</li><li>Collaborate with manufacturing, quality, supply chain, and external partners.</li></ul>Required Knowledge & SkillsEngineering & Technical Expertise<ul><li>Strong knowledge of engineering first principles.</li><li>Proven technical judgment and problem-solving abilities.</li><li>Experience with R&D functional planning, requirement generation, and technical reviews across all product development phases.</li><li>Proficiency with solid modeling tools such as Pro/ENGINEER (Creo), SolidWorks, or equivalent.</li><li>Proficiency in fixture design, basic machining considerations, and test method development.</li><li>Understanding of high-volume, tightly controlled manufacturing processes.</li></ul>Methodologies & Quality Systems<ul><li>Strong understanding of Six Sigma (DMAIC) and Design for Six Sigma (DFSS) methodologies.</li><li>Knowledge of Measurement Systems Analysis (MSA).</li><li>Experience working within phase-gate product development processes.</li></ul>Project & Leadership Skills<ul><li>Strong project management, prioritization, and multitasking skills.</li><li>Ability to work independently with minimal direction.</li><li>Experience leading small cross-functional teams or directing associates.</li><li>Proficiency with Microsoft Project or similar project planning tools.</li></ul>Communication<ul><li>Excellent written and verbal communication skills.</li><li>Ability to clearly communicate technical concepts, risks, and recommendations to diverse audiences.</li></ul>Preferred Qualifications<ul><li>Experience in the medical device or life sciences industry.</li><li>Hands-on experience with statistical tools and experimental analysis software.</li><li>Experience supporting supplier development and component qualification.</li></ul> <ul><li>Seniority Level Mid-Senior level</li><li>Industry</li><li><ul><li>Medical Equipment Manufacturing</li></ul></li><li>Employment Type Contract</li><li>Job Functions</li><li><ul><li>Engineering</li></ul></li><li>Skills</li><li><ul><li>Medical Device Product Dev</li></ul></li></ul></div></div>

Calculate Moving Average	SQL	Easy
Predict Customer Churn	Machine Learning	Medium
A/B Test Significance	Statistics	Medium
Optimize Query Performance	SQL	Hard
Feature Importance Analysis	Machine Learning	Medium
Clean Missing Data	Python	Easy
Neural Network Architecture	Deep Learning	Hard
Calculate Cohort Retention	SQL	Medium
Bayesian Probability	Statistics	Easy
Recommend Similar Products	Machine Learning	Hard

A-Line Staffing Solutions Interview Questions

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A-Line Staffing Solutions Interview Questions

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